Orphan marker

Finished proposals should not be deleted, but marked as orphan. This
marker should have the following content:

To the name of the proposal the following tag will be added:
"[QA-ORPHAN]".

To the describtion of the proposal the following text will be
added at the top: "This proposal has been marked orphan by
PEAR-QA on <DATE> because of the inactivity of the proposer.
This means, that the proposal is invalid from this date on. If you
have a similar proposal or want to re-activate this proposal, feel
free to create a new PEPr proposal for it.".